1. Field of the Invention
The present invention, which relates to electric frequency filters used in telecommunication circuits, concerns filter cells whose transfer function expressed as a function of angular frequency is equal to the quotient of two polynomials of at least second degree.
2. Description of the Prior Art
Among the conventional active filter cells of this type, one of the simplest is the subject of the French patent No. 2,024,177 filed on Nov. 24th, 1969 by Western Electric Co. Inc. However, in solving certain special problems, this simplicity is not always retained. For instance, when the pass-band of the filter contains several regions separated by high attenuation frequencies, it is necessary to combine as many cells as there are regions of transmitted frequencies.